1 EECS-149 April 29, 2009 Network Time Synchronization with IEEE 1588 (Time Distribution in Embedded Systems) John C. Eidson [email protected]Office 545Q Cory Hall (Tuesdays and Fridays) EECS-149 Slide 2 April 29, 2009 Agenda 1. Major time distribution systems used in embedded systems 2. How, where and why they are used 3. Application examples 4. Time distribution- in particular IEEE 1588- as an embedded system
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1. Major time distribution systems used in embedded systems
2. How, where and why they are used
3. Application examples
4. Time distribution- in particular IEEE 1588- as an embedded system
2
EECS-149
Slide 3 April 29, 2009
Major time distribution systems used in embedded systems
1. NTP- c <1985, ~10ms
2. GPS- c 1972, operational in 1993,~100ns: (Glonass, Galileo )
3. IRIG-B- c 1960, ~1-10 us
4. IEEE 1588-2008 – c 2002, ~20ns on Ethernet
5. Proprietary or controlled protocols, e.g. FlexRay(c ~2000),
TTP(c ~1993), TTE(c ~2005)…
EECS-149
Slide 4 April 29, 2009
Purpose of IEEE 1588
NETWORK
IEEE 1588 is a protocol designed to synchronize real-time
clocks in the nodes of a distributed system that communicate
using a network
• It does not say how to use these clocks (this is specified by the respective
application areas)
3
EECS-149
Slide 5 April 29, 2009
Coupling IEEE 1588 to your application(This is your job- the standard has no opinion on how it is used)
IE E E 1 5 8 8 C lo c k
L a tc htr ig g e r- in
t im e s ta m pg e n e ra t in g t im e s ta m p s
IE E E 1 5 8 8 C lo c k
C o m p a ra to r tr ig g e r-o u t
e v e n t t im e g e n e ra t in g e v e n ts
L a tc h
IE E E 1 5 8 8 C lo c k S yn th e s iz e r w a v e fo rm
g e n e ra t in g w a v e fo rm s
EECS-149
Slide 6 April 29, 2009
Where is IEEE 1588 being (or likely to be used)?
1. Power generation (>50K nodes in service)
2. Industrial automation (esp. motion control)
3. Telecom (cellular backhaul initially- already field installations)
4. Audio visual systems (as IEEE 802.1AS a specialization of
1588)
5. Military, aerospace, instrumentation (flight qualification, surveillance, data acquisition)
6. Other nascent applications
4
EECS-149
Slide 7 April 29, 2009
RoboTeam in Action: Process Relative Motion
Courtesy of Kuka Robotics
Corp.
EECS-149
Slide 8 April 29, 2009
e.g. high speed printing Courtesy of Bosch-Rexroth.
60 mph ~= 0.001 in/us
5
EECS-149
Slide 9 April 29, 2009
IEEE 1588 enabled flight test instrumentation in the forward fuselage of a test aircraft. (Data acquisition)
Courtesy of Teletronics
EECS-149
Slide 10 April 29, 2009
Cellular backhaul is the major telecom application to date. Metro-
Ethernet in field trial. Femtocells beginning.
Companies involved (partial list):
• Nokia-Siemens, Brilliant, Semtech, Zarlink, …
Telecommunications Applications
6
EECS-149
Slide 11 April 29, 2009
IEEE Power System Relaying Committee (PSRC) recently approved formation
of Working Group H7 "IEEE 1588 Profile for Protection Applications"
Power System Applications
EECS-149
Slide 12 April 29, 2009
GE uses 1588 in the Mark™VIe control system for large generators, turbines, wind farms, and other DCS applications. (>50K I/O Packs with 1588 shipped to date)
LANThere are PRET design issues! The specifics differ depending on where the 1588 components are located, e.g. at task, ISR, MII, or in the PHY or some combination thereof!
EECS-149
Slide 32 April 29, 2009
Clock Rate Servo (Software portion)
Z-11-f
f∑+ S2M Delay
∑
D_rsp (TS4)
D_req (TS3)
-
++
Z-11-f
f∑+ M2S Delay
∑
S_rcv (TS2)
S_snd (TS1)
-
++
∑+
+1/2
One-Way Delay
∑+
-P
T ∑
Z-1
+
+
∑
109
+-
- Clock Rate
Err
I
Clock rate signal drives hardware (or software)
rate adjust
This is a closed loop control system so loop time does matter- hence a
PRET design issue!
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EECS-149
Slide 33 April 29, 2009
Coupling IEEE 1588 to your application: Critical issues
IE E E 1 5 8 8 C lo c k
L a tc htr ig g e r- in
t im e s ta m pg e n e ra t in g t im e s ta m p s
IE E E 1 5 8 8 C lo c k
C o m p a ra to r tr ig g e r-o u t
e v e n t t im e g e n e ra t in g e v e n ts
L a tc h
IE E E 1 5 8 8 C lo c k S yn th e s iz e r w a v e fo rm
g e n e ra t in g w a v e fo rm s
Hard real-world time:
Application specific but high node value apps <1 us,
military/surveillance <5ns
‘uProcessor’ time
EECS-149
Slide 34 April 29, 2009
National Semiconductor DP83640 PHYTER(from DP83640 datasheet)
Hard
real-world
time
‘uProcessor’ time
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EECS-149
Slide 35 April 29, 2009
National Semiconductor DP83640 PHYTERSimple, Accurate Time Synchronization in an Ethernet Physical Layer Device, David Rosselot, ISPCS 2007